I definitely wasn't offered any free seats. I was told there was a charge to select any seat ($12) with the front seats at $20 and exit row at $25 (but don't quote me on the exit row price). I ended up paying the $20 for the front seats, which I wanted anyway, but was just surprised to see that seat selection should be free on avois bookings. Maybe US agents aren't as familiar with this policy? Or maybe there is a difference with EI avios and BA avios?